Studies on catalysis by transition metal promoted sulphated zirconia

The present project was a systematic investigation of the physico-chemical properties and catalytic activity of some transition metal promoted sulphated zirconia systems. The characterisation and catalytic activity results were compared with that of pure Zr02 and simple sulphated zirconia systems. Sulphated zirconia samples were prepared by a controlled impregnation technique. In the case of metal incorporated systems, a single step impregnation was carried out using required amounts of sulphuric acid and metal salt solutions. As a preliminary step, optimisation of calcination temperature and sulphate content was achieved. For further studies, the optimised sulphate loading of 10 ml per gram of hydrous zirconium oxide and a calcination temperature of 700°C was employed. Metal incorporation had a positive influence on the physico-chemical properties. Vapour phase cumene conversion served as a test reaction for acidity. Some industrially important reactions like Friedel-Crafts reaction, phenol hydroxylation, nitration, etc. were selected to test the catalytic activity of the prepared systems.

Acid-Base. Surface Electron Donatin6 &.Catai.Ytlc Properties Of Some Binary Mixed Oxides Containing Rare Earth Elements

Catalysis research underpins the science of modern chemical processing and fuel technologies. Catalysis is commercially one of the most important technologies in national economies. Solid state heterogeneous catalyst materials such as metal oxides and metal particles on ceramic oxide substrates are most common. They are typically used with commodity gases and liquid reactants. Selective oxidation catalysts of hydrocarbon feedstocks is the dominant process of converting them to key industrial chemicals, polymers and energy sources.[1] In the absence of a unique successfiil theory of heterogeneous catalysis, attempts are being made to correlate catalytic activity with some specific properties of the solid surface. Such correlations help to narrow down the search for a good catalyst for a given reaction. The heterogeneous catalytic performance of material depends on many factors such as [2] Crystal and surface structure of the catalyst. Thermodynamic stability of the catalyst and the reactant. Acid- base properties of the solid surface. Surface defect properties of the catalyst.Electronic and semiconducting properties and the band structure. Co-existence of dilferent types of ions or structures. Adsorption sites and adsorbed species such as oxygen.Preparation method of catalyst , surface area and nature of heat treatment. Molecular structure of the reactants. Many systematic investigations have been performed to correlate catalytic performances with the above mentioned properties. Many of these investigations remain isolated and further research is needed to bridge the gap in the present knowledge of the field.